Would a stress test tell if you have hardening of the arteries?

Not always : 15% times stress test is wrong.

Not Necessarily: Stress tests detect blockage sufficient to limit blood flow in a vessel. Non-invasive imaging, such as coronary calcium score (ccs) and carotid ultrasound for intima-media thickness (cimt), can detect earlier, non-flow limiting, atherosclerosis. Ccs quantifies calcium in mature artery plaques. Cimt measures earlier changes of vascular disease (cimt thickness and small plaques without calcium).